memaslap - Load testing and benchmarking a server
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SYNOPSIS
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.. envvar:: MEMCACHED_SERVERS
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DESCRIPTION
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:program:`memaslap` is a load generation and benchmark tool for memcached
servers. It generates configurable workload such as threads, concurrency,
connections, run time, overwrite, miss rate, key size, value size, get/set
You can specify servers via the :option:`memslap --servers` option or via the
environment variable :envvar:`MEMCACHED_SERVERS`.
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FEATURES
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Memslap is developed to for the following purposes:
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Manages network connections with libevent asynchronously.
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Set both TCP and UDP up to use non-blocking IO.
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Improves parallelism: higher performance in multi-threads environments.
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Improves time efficiency: faster processing speed.
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Generates key and value more efficiently; key size distribution and value size distribution are configurable.
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Supports get, multi-get, and set commands; command distribution is configurable.
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Supports controllable miss rate and overwrite rate.
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Supports data and expire-time verification.
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Supports dumping statistic information periodically.
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Supports thousands of TCP connections.
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Supports binary protocol.
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Supports facebook test (set with TCP and multi-get with UDP) and replication test.
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DETAILS
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Effective implementation of network.
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For memaslap, both TCP and UDP use non-blocking network IO. All
the network events are managed by libevent as memcached. The network module
of memaslap is similar to memcached. Libevent can ensure
memaslap can handle network very efficiently.
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Effective implementation of multi-threads and concurrency
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Memslap has the similar implementation of multi-threads to
memcached. Memslap creates one or more self-governed threads;
each thread is bound with one CPU core if the system tests setting CPU
concurrency and socket connections of each concurrency according to their
expected workload.
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Effective implementation of generating key and value
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-In order to improve time efficiency and space efficiency,
+In order to improve time efficiency and space efficiency,
memaslap creates a random characters table with 10M characters. All the
suffixes of keys and values are generated from this random characters table.
time, each concurrency kicks objects out of its window and adds new object
into it.
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Simple but useful task scheduling
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Memslap uses libevent to schedule all concurrent tasks of
threads, and each concurrency schedules tasks based on the local task
window. Memslap assumes that if each concurrency keeps the same
specify the window size to get the expected miss rate of the first cache
layer.
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Useful implementation of multi-servers , UDP, TCP, multi-get and binary protocol
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Because each thread is self-governed, memaslap can assign
different threads to handle different memcached servers. This is just one of
the ways in which memaslap tests multiple servers. The only
get lost, the waiting timeout mechanism can ensure half-baked packages will
be discarded and the next command will be sent.
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USAGE
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Below are some usage samples:
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memaslap -s 127.0.0.1:11211 -S 5s
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memaslap -s 127.0.0.1:11211 -t 2m -v 0.2 -e 0.05 -b
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memaslap -s 127.0.0.1:11211 -F config -t 2m -w 40k -S 20s -o 0.2
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memaslap -s 127.0.0.1:11211 -F config -t 2m -T 4 -c 128 -d 20 -P 40k
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memaslap -s 127.0.0.1:11211 -F config -t 2m -d 50 -a -n 40
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memaslap -s 127.0.0.1:11211,127.0.0.1:11212 -F config -t 2m
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memaslap -s 127.0.0.1:11211,127.0.0.1:11212 -F config -t 2m -p 2
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The user must specify one server at least to run memaslap. The
rest of the parameters have default values, as shown below:
Facebook test = false Replication test = false
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Key size, value size and command distribution.
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All the distributions are read from the configuration file specified by user
with "—cfg_cmd" option. If the user does not specify a configuration file,
memaslap will run with the default distribution (key size = 64,
testss 100% set and 100% get. For 100% get, it will preset some objects to
the server.
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Multi-thread and concurrency
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The high performance of memaslap benefits from the special
schedule of thread and concurrency. It's important to specify the proper
number of them. The default number of threads is 1; the default number of
the throughput equal to or less than the maximum
throughput using "--tps" option.
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Window size
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Most of the time, the user does not need to specify the window size. The
default window size is 10k. For Schooner Memcached, the user can specify
different window sizes to get different cache miss rates based on the test
cache_size / concurrency / (key_size + value_size) \* 0.7
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Verification
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Memslap testss both data verification and expire-time
verification. The user can use "--verify=" or "-v" to specify the proportion
of data verification. In theory, it testss 100% data verification. The
verification. Specify the "--verbose" options to get more detailed error
information.
-For example: --exp_verify=0.01 –verify=0.1 , it means that 1% of the objects
+For example: --exp_verify=0.01 –verify=0.1 , it means that 1% of the objects
set with expire-time, 10% of the objects gotten will be verified. If the
objects are gotten, memaslap will verify the expire-time and
value.
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multi-servers and multi-config
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Memslap testss multi-servers based on self-governed thread.
There is a limitation that the number of servers cannot be greater than the
number of threads. Memslap assigns one thread to handle one
All the threads and concurrencies in memaslap are self-governed.
-So is memaslap. The user can start up several
+So is memaslap. The user can start up several
memaslap instances. The user can run memaslap on different client
machines to communicate with the same memcached server at the same. It is
recommended that the user start different memaslap on different
machines using the same configuration.
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Run with execute number mode or time mode
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The default memaslap runs with time mode. The default run time
is 10 minutes. If it times out, memaslap will exit. Do not
specify both execute number mode and time mode at the same time; just
--execute_number=100000 (It means that after running 100000 commands, the test will exit.)
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Dump statistic information periodically.
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The user can use "--stat_freq=" or "-S" to specify the frequency.
For example:
For more information on the format of dumping statistic information, refer to "Format of Output" section.
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Multi-get
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The user can use "--division=" or "-d" to specify multi-get keys count.
Memslap by default does single get with TCP. Memslap also testss data
verification and expire-time verification for multi-get.
binary protocol, memaslap sends several single get commands
together as "multi-get" to the server.
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UDP and TCP
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Memslap testss both UDP and TCP. For TCP,
memaslap does not reconnect the memcached server if socket connections are
lost. If all the socket connections are lost or memcached server crashes,
UDP doesn't tests reconnection.
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Facebook test
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Set data with TCP and multi-get with UDP. Specify the following options:
"--facebook --division=50"
If you specify "--division=50", the key size must be less that 25 bytes
because the UDP packet size is 1400 bytes.
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Replication test
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For replication test, the user must specify at least two memcached servers.
The user can use "—rep_write=" option to enable feature.
back to life again, memaslap will reconnect server 0. If both
server 0 and server 1 crash, memaslap will exit.
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Supports thousands of TCP connections
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Start memaslap with "--conn_sock=" or "-n" to enable this
feature. Make sure that your system can tests opening thousands of files
and creating thousands of sockets. However, this feature does not tests
connections, and the total number of TCP socket connections is 128 \* 128 =
16384.
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Supports binary protocol
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Start memaslap with "--binary" or "-B" options to enable this
feature. It testss all the above features except UDP, because the latest
memcached 1.3.3 does not implement binary UDP protocol.
multi-get. If you specify "--division=50" option, it just sends 50 get
commands together as "multi-get" to the server.
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Configuration file
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This section describes the format of the configuration file. By default
when no configuration file is specified memaslap reads the default
one located at ~/.memaslap.cnf.
Below is a sample configuration file:
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.. code-block:: perl
---------------------------------------------------------------------------
0 0.1
1.0 0.9
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Format of output
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At the beginning, memaslap displays some configuration information as follows:
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servers : 127.0.0.1:11211
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threads count: 1
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concurrency: 16
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run time: 20s
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windows size: 10k
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set proportion: set_prop=0.10
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get proportion: get_prop=0.90
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Where
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servers : "servers"
The servers used by memaslap.
The output of dynamic statistics is something like this:
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.. code-block:: perl
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117.93 195.60
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Where
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Get Statistics
Statistics information of get command
At the end, memaslap will output something like this:
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.. code-block:: perl
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Where
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Get Statistics
Get statistics of response time
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OPTIONS
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-s, --servers=
List one or more servers to connect. Servers count must be less than
threads count. e.g.: --servers=localhost:1234,localhost:11211
The proportion of objects need overwrite, e.g.: --overwrite=0.01.
Default never overwrite object.
--R, --reconnect
+-R, --reconnect
Reconnect tests, when connection is closed it will be reconnected.
--U, --udp
+-U, --udp
UDP tests, default memaslap uses TCP, TCP port and UDP port of
server must be same.
--a, --facebook
+-a, --facebook
Whether it enables facebook test feature, set with TCP and multi-get with UDP.
--B, --binary
+-B, --binary
Whether it enables binary protocol. Default with ASCII protocol.
-P, --tps=
-p, --rep_write=
The first nth servers can write data, e.g.: --rep_write=2.
--b, --verbose
+-b, --verbose
Whether it outputs detailed information when verification fails.
--h, --help
+-h, --help
Display this message and then exit.
--V, --version
+-V, --version
Display the version of the application and then exit.
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EXAMPLES
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memaslap -s 127.0.0.1:11211 -S 5s
memaslap -s 127.0.0.1:11211 -t 2m -v 0.2 -e 0.05 -b
memaslap -s 127.0.0.1:11211,127.0.0.1:11212 -F config -t 2m -p 2
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SEE ALSO
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projects / awesomized / libmemcached / blobdiff